Title :
Principles for timing at spallation neutron sources based on developments at LANSCE
Author :
Nelson, R. ; Merl, R. ; Rose, C.
Author_Institution :
Los Alamos Nat. Lab., NM, USA
Abstract :
Due to AC-power-grid frequency fluctuations, the designers for accelerator-based spallation-neutron facilities have worked to optimize the conflicting demands of accelerator and neutron chopper performance. For the first time, we are able to quantitatively access the tradeoffs between these two constraints and design or upgrade a facility to optimize total system performance using powerful new simulation techniques. We have modeled timing systems that integrate chopper controllers and chopper hardware and built new systems. Thus, at LANSCE, we now operate multiple chopper systems and the accelerator as simple slaves to a single master-timing-reference generator. Based on this experience we recommend that spallation neutron sources adhere to three principles. First, timing for pulsed sources should be planned starting with extraction at a fixed phase and working backwards toward the leading edge of the beam pulse. Second, accelerator triggers and storage ring extraction commands from neutron choppers offer only marginal benefits to accelerator-based spallation sources. Third, the storage-ring RF should be phase synchronized with neutron choppers to provide extraction without the one orbit timing uncertainty
Keywords :
beam choppers; neutron sources; particle beam extraction; proton accelerators; storage rings; timing; AC-power-grid frequency fluctuations; LANSCE; accelerator triggers; accelerator-based spallation sources; multiple chopper systems; neutron chopper performance; pulsed sources; spallation neutron sources; storage ring extraction commands; total system performance; Acceleration; Choppers; Constraint optimization; Design optimization; Fluctuations; Frequency; Neutrons; Power system modeling; System performance; Timing;
Conference_Titel :
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-7191-7
DOI :
10.1109/PAC.2001.986478